Silica, i.e., silicon dioxide, nanoparticles can be used as, for example, catalysts, stabilizers, and pigments in a variety of industries. The quality of the silica nanoparticles depends on their size and size distribution. There are numerous methods for synthesizing silica nanoparticles to have a small size and narrow size distribution, such as flame spray pyrolysis, water-in-oil microemulsion, bead milling, continuous microwave hydrothermal synthesis, and self-assembly. For example, silica particles ranging from 5 nm to several microns in diameter have been synthesized.
Rare earth oxide nanoparticles are of interest because of their catalytic, electronic, magnetic, and optical properties. Rare earth oxide core-shell nanoparticles are of particular interest because they exhibit multiple functions that do not exist in single-component compounds. For example, both the core and the shell of some rare earth oxide core-shell nanoparticles have been found to be actively involved in catalytic processes. However, a new, more economical method is needed to prepare rare earth oxide core-shell nanoparticles, such as silica-dysprosium oxide core-shell nanoparticles.